I think the amendment introduced is quite complete. Where you state “any other person who boards a ship without the consent [...]”, that doesn't make me think of the officers who are the representatives of the port or government because, in any case, the captain gives the individual his consent to board the ship.
The definition of “stowaways” can be very restrictive. The same is true of the definition of trespasser. That could be a friend of a passenger or someone who says he isn't a stowaway, that he isn't a trespasser, even though he hasn't paid and someone didn't know he was there.
That's why I think that “any other person who boards a ship without the consent or knowledge [...]” is a more comprehensive definition. I therefore hope that the government won't amend it. I would support it as it stands right now, in view of the objective you are pursuing. If there is another one, perhaps we should review the subsection in full.
Let's see whether I understand the objective when you talk about stowaways and trespassers. Sometimes there are people who might be friends of the crew and who would say they aren't stowaways, that they aren't himtrespassers, whereas the captain or the authorities didn't know they were there.
I think your definition is more comprehensive; I like it as it is.